Actor Zachary Quinto has called for NSA whistleblower Edward Snowden to be allowed to return to America without facing espionage charges.

The Star Trek actor said Snowden had acted with "great courage" and it was "absurd" to brand him a "treasonist" while he remains in exile in Russia.

Zachary plays journalist Glenn Greenwald in Oliver Stone's new film Snowden, which tells the story of how the former NSA analyst leaked details of mass government surveillance in 2013.

Zachary Quinto (Jordan Strauss/Invision/AP)

Speaking at the film's premiere in Toronto, Zachary - known for his role as Spock in the rebooted Star Trek films - told the Press Association: "I do think (Mr Snowden) should be able to come back (to America). I think it's a very complicated issue in terms of how that would happen.

"The idea of him being charged under the Espionage Act or branded as a treasonist is absurd. I think he is someone of great integrity and great courage.

"I think what he did is underestimated now, in a lot of ways, but I think will be looked back on with the magnitude it deserves.

Edward Snowden (Marco Garcia/AP)

"Hopefully he can enjoy some freedoms again in his life. He deserves that in my opinion."

Snowden faces charges in the US under the Espionage Act that could land him in prison for up to 30 years. He has previously said he would return to America if he was guaranteed a fair trial.

Actor Joseph Gordon-Levitt said he was "honoured" to portray Mr Snowden in the film and he had a "valuable" four-hour meeting with the whistleblower in Moscow.

Joseph Gordon-Levitt at the Snowden premiere in Toronto (Chris Pizzello/Invision/AP)

Speaking at the premiere, he said: "There were voices in my professional life who said, 'He's a controversial figure, you know this might not be the most commercially viable choice to make'. It's not how I made my decision.

"In reading up on him and really learning about what he did and why he did it, I felt grateful for what he did and honoured I got to play him.

"I don't think a single label is appropriate. Everyone tries to simplify this story. It's not simple, it's complicated.

Joseph Gordon-Levitt (Chris Pizzello/Invision/AP)

"I would encourage anybody to look into it themselves rather than taking one quick soundbite or tweet and thinking you have an understanding of what's really happening."

Snowden is to be screened at the London Film Festival on October 15.

Let us send you our Newsletter

Our editors will email you a roundup of their favourite stories from across AOL